An in vitro evaluation of the effects of desensitizing agents on microleakage of Class V cavities

Background: The aim of this study was to evaluate the effect of a desensitizing agent on microleakage of Class V cavities. Material and Methods: 72 premolar teeth were used. There were 6 groups. Class V restorations were prepared with two different restorative materials (Equia fil, GC, America and Grandio, VOCO, Germany) and two adhesive systems (Clearfil SE Bond, Kuraray, Japan and S3 Bond Plus, Kuraray, Japan) with and without desensitizing agent (Gluma Desensitizer, Heraeus Kulzer, Germany). Restorations were polished with aluminum oxide abrasive discs. Then a range of 5 - 55C thermocycling was performed 10.000 times. The microleakage of restorations was examined with dye penetration method (Basic fuchsine). Bonferroni corrections and Kruskal-Wallis test were used to determine the significance of differences in occlusal and gingival dye penetration scores between groups. Results: There was no stastistical significance between the occlusal and gingival microleakage scores within the groups were shown. Conclusions: It can be concluded that use of desensitizing agent under both high viscosity glass ionomer restorative materials and resin composites doesn’t affect the microleakage

Propolis içeren çinko oksit öjenol esaslı deneysel kök kanal patlarının fiziksel özelliklerinin standart patlarla in vitro olarak karşılaştırılması

Amaç: Bu çalışmanın amacı propolis içeren çinko oksit öjenol esaslı deneysel patların (PP) fiziksel özelliklerinin ve mikrosızıntısının Grossman patı ve AH Plus ile karşılaştırılmasıdır. Gereç ve Yöntem: Bu çalışmada, Tekirdağ yöresinden (Trakya bölgesi, Türkiye) toplanılan propolis kullanıldı. Değişik oranlarda propolis içeren patlar [%5 (PP5), %10 (PP10), %25 (PP25), %50 (PP50)], Grossman patı ve AH Plus ile karşılaştırıldı. Film kalınlıkları, akıcılıkları, radyoopasiteleri, sertleşme süreleri, çözünürlükleri ve sudaki ekstraktlarının pH’ları ISO 6876/2001 standartlarına göre değerlendirildi. Patların mikrosızıntıları bilgisayarlı sıvı filtrasyon yöntemiyle incelendi. İstatistiksel analizde pH için Friedman testi, diğer tüm testlerin analizinde Kruskal-Wallis testi kullanıldı (α=0.05). Bulgular: PP’lerin çözünürlük hariç diğer fiziksel özellikleri ISO 6876/2001 standartlarına uygundu. PP’lerin çözünürlüğü Grossman patına benzer (p>0.05), AH Plus’tan anlamlı şekilde fazlaydı (p<0.05). Gruplar-arası pH karşılaştırmasında, PP’lerin sudaki ekstratlarının pH’si Grossman ve AH Plus patlarına benzer veya istatistiksel olarak onlardan daha yüksekti (p<0.05). Grup-içi karşılaştırmalarda da anlamlı farklar bulunmakla beraber (p<0.05), pH değerlerinin zaman ile yükselme eğiliminde olduğu görüldü. Mikrosızıntı için en yüksek değerler PP5’te ve Grossman patında (p>0.05; ikisi birbirine benzerdi), en düşük değerler ise AH Plus’ta görüldü; PP10, PP25 ve PP50 bunların arasında idi. Sonuç: Propolis patlarının fiziksel özelliklerinin çoğunun ISO 6876/2001 standartlarına uygun bulunması, mikrosızıntılarının Grossman patından daha az olması ve sudaki ekstraktlarının pH’lerinin uygun olması gelecekte olası klinik kullanımları için umut vericidir

HPLC analysis of monomers eluted from self-adhesive resin cements

OBJECTIVE: The aim of this study was to determine the residual monomer leaching from two self-adhesive resin cements polymerized with Light Emitting Diode (LED) or halogen light curing unit. MATERIALS AND METHOD: Clearfil SA (group A, n = 48) and BisCem (group B, n = 48) cements were inserted in plastic moulds. Each group was further divided into two subgroups. Specimens were light cured with LED light curing unit (LCU) in group A1 and group B1 and halogen LCU in group A2 and group B2 for 20 seconds. The following compounds released from the samples stored in distilled water were analyzed: triethylene glycol-dimethacrylate (TEGDMA) and bisphenol A glycidyl methacrylate (Bis-GMA). Analysis of substances was performed with the use of high performance liquid chromatography, after 1 hour and 24 hour incubation periods. Factorial experimental design and independent t-test was used for statistical analyses. RESULTS: Self-adhesive resin cements released more Bis-GMA and TEGDMA when they were polymerized with LED LCUs (p0.05). Clearfil SA cement released more Bis-GMA than BisCem (p<0.05). BisCem released more TEGDMA than Clearfil SA (p<0.05). CONCLUSION: The results of this study showed that the quantity of Bis-GMA and TEGDMA leached from self-adhesive resin cements was influenced by the type of LCU and by the type of self-adhesive resin cement

Effect of using different base materials on microleakage of class V restorations

Objective: The aim of this in vitro study was to evaluate and compare the effect of using different base materials on microleakage of class V restorations. Materials and Method: In this study 60 extracted non-cavitated human molar teeth were used. Class V cavities were prepared on the buccal surfaces in 4 mm mesio-distal, 3 mm gingivo-occlusal width and 3 mm depth. The teeth were randomly divided into five groups: Group 1: resin-modified calcium silicate material (TheraCal LC), Group 2: self-adhesive flowable composite resin (Fusio Liquid Dentin), Group 3: flowable composite resin liner (Tetric N Flow), Group 4: resin-modified glass ionomer liner (Ketac N100), Group 5: control group. Materials in the experimental groups were placed in 1 mm thickness as liner. Then, a nanohybrid composite resin (Grandio) was placed and restorations were completed. In the control group, no base material was applied. After finishing and polishing procedures, thermocycling was performed 5000 times between 5-55 °C. Microleakage of restorations was evaluated by using dye penetration method (basic fuchsin). Results were analyzed by Kruskal Wallis with Bonferroni correction and Mann-Whitney U tests. Results: Regarding occlusal microleakage, no statistically significant difference was found between the groups (p=0.267); however significant difference was found between the gingival microleakage scores (p=0.004). Compared to Fusio Liquid Dentin and control groups, significantly less dye penetration was found in Theracal LC, Tetric N-Flow and Ketac N-100 groups (p0.01). Conclusion: Within the limitation of this study, the conclusion was that the use of a liner (except Fusio Liquid Dentin) under composite resin in a class V cavity reduced the microleakage of the restoration

Examination of gutta-percha cones for microbial contamination during chemical use

OBJECTIVE: The aim of this study was to evaluate the degree of microbial contamination in packaged gutta-percha cones before and during use in clinical conditions. MATERIAL AND METHODS: Sealed packages of #15-40 gutta-percha cones were opened under aseptic laboratory conditions. Two gutta-percha cones from each size were randomly drawn and added to tubes containing glass beads and 750 µL of saline. The tubes were vortexed, serially diluted and samples of 250 µL were cultured on agar plates. The plates were incubated at 37ºC for 3 days and colonies were counted. The initially sampled packages were distributed to 12 final year dental students. The packages were collected at the end of the first and the third clinical practice days and sampled as described above. RESULTS: Baseline microbial counts did not exceed 3 CFU. At the end of the first and the third day, additional contamination was found in five and three of the packages, respectively. The ratio of contaminated packages at the first day and the third day was not significantly different (z-test; p > 0.05). The numbers of microorganisms cultured at the first day (8 ± 9.9 CFU) and the third day (4.5 ± 8.3 CFU) were not significantly different (Wilcoxon signed-rank test; p > 0.05). No significant correlation was found between the number of filled root canals and cultured microorganisms at either the first day (Spearman's rho; r = 0.481, p = 0.113) or the third day (r = -0.034, p = 0.917). CONCLUSIONS: Gutta-percha cones taken directly from manufacturer's sealed package harbored microorganisms. Clinical use of the packages has been found to be associated with additional contamination of the gutta-percha cones. The counts of cultured microorganisms did not correlate well with the number of filled root canals